排序方式: 共有20条查询结果,搜索用时 15 毫秒
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用软件无线电实现MPSK自适应调制 总被引:2,自引:0,他引:2
自适应调制能够根据信道的时变性达到很高的传输速率和进行合理的功率分配.同时,它需要自适应调整调制模式级别M.采用软件方式在DSP板上能够实现MPSK的调制、解调功能和调制模式M的识别,替代在硬件之间进行切换的繁琐模式.调制器根据星座图和已知的调制级别在己存储的波形中挑选对应的调制波形,解调器在信号同步的情况下通过使用最小均方进行解调,同时进行M模式识别.模拟结果显示用软件无线电方式实现MPSK自适应调制是一条简捷快速的途径.特别在自适应调制中加入LDPC(低密度校验码)编码和一种新的结合BP和list-based SI HO解码后,系统性能更为优异. 相似文献
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推导了存在相位误差,正交误差和I-Q增益不平衡时,相干MPSK系统在莱斯信道下的误符号率,并以相干MPSK系统仅存在正交误差为例进行了仿真.仿真结果表明,该误符号率的数值解与已有文献相同,验证了理论分析的正确性. 相似文献
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MPSK信号的循环谱检测及码元速率估计 总被引:23,自引:1,他引:23
在循环平稳理论的基础上,根据MPSK信号的循环平稳特性及其在普通傅里叶频率和循环频率双频率平面上所表现出的谱线特征,提出了一种在低信噪比下,利用两次谱峰搜索完成对MPSK信号的检测及载频和码元速率估计的新方法。该方法估计精度高,计算机仿真证明了该方法的有效性。 相似文献
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This paper presents an improved non-data-aided algo-rithm for carrier frequency estimation for burst M-ary PSK signals when modulation order M and training symbols are unknown. Unlike data-aided estimation, a phase clustering algorithm is used first to estimate M and modulated information is removed by a vari-able interval linear phase unwrapping. Then, a high-order correlation algorithm with proper correction is present, which reduces the probability of phase ambiguity and promotes anti-noise capability of the estimation. Simulations are given to analyze the unbiased esti-mation range, and the asymptotic performance and symbol number are needed to compare with the former algorithms. The new algo-rithm has a large estimation range close to the theoretical maximum value for non-data-aided estimation and has a better performance than earlier non-data-aided techniques for large frequency offset, low signal-to-noise ratio, and limited symbol numbers. 相似文献
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A phase-domain blind estimator of symbol duration based on Haar wavelet transform (HWT) is proposed. It can estimate the symbol duration of phase modulated signals, such as M-ary phase-shift keying (MPSK) signals and polyphase coded signals. The closed form of the spectrum of HWT is derived. Theoretical analysis shows the frequency of the first spectral peak is equal to the symbol rate, which is the reciprocal of symbol duration. Thus the symbol duration can be extracted from the spectrum. Subsequently, the optimum wavelet scale is determined according to the maximum output signal to noise ratio (OSNR) criterion. MATLAB simulations show that this algorithm can blindly estimate the symbol duration without any prior knowledge. This estimator need not estimate the carrier frequency and has the characteristics of low computation complexity and high accuracy. 相似文献
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在小波分析的理论基础上,提出使用高斯(Gaussian)小波进行连续小波变换,进而提取信号的小波变换后的幅度,获取其瞬时特征,达到识别MPSK(M-ary Phase Shift Keying)与MFSK(Multi-Frequency Shift Keying)信号的目的,从而在不需要先验知识的情况下识别接收信号的调制方式的目的.验证该方法较现有文献利用Haar小波变换识别信号方法具有更好的性能,而且克服了现有文献采用Haar小波变换识别调制信号的漏检问题,提高了运算速度和性能,并有效增加了小波变换识别调制信号方法的适用性.通过理论分析和计算机仿真证实了新方法的有效性和优越性. 相似文献
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根据北京地区的场测试结果 ,给出了适合于该地区的服从M分布的移动信道仿真模型 ,为研究中国地区的差错控制方案提供了平台 .在此基础上 ,研究了RS码与MPSK相结合的方案在此信道模型中的性能 .仿真结果表明 :在适应于北京地区的M衰落信道中 ,RS码与MPSK相结合方案在不增加频带带宽的前提下 ,与未编码的QPSK相比较 ,在Pb =1 0 - 3时 ,可有 1 0dB的编码增益 . 相似文献